From bcf2694f937703c6429aee5ba8ed5959e8b4b444 Mon Sep 17 00:00:00 2001 From: Chris Teague Date: Fri, 12 Feb 2021 14:26:42 -0800 Subject: Make func_800C213C match original ROM (#678) * Make func_800C213C match original ROM The C code for this function was very close to done, and was functionally equivalent to the ROM. This commit uses a few tricks to convince the compiler to allocate the same registers as the original ROM. The two tricks used are: 1. Introduced a new temporary variable "yinc". 2. Added a "do while(0) {}" line in two places. Both of these ideas came from the decomp-permuter tool. I took the do/while idea and guess as to what it might have been in the original code. I imagined that the "do while(0) {}" was probably left over from a standard multi-line macro, which for some reason had an empty body. I further suggest that maybe the empty body is because it was a feature compiled out during RELEASE builds - perhaps a debug logging macro. * Use simpler code for func_800C213C Replaced dummy LOG macro with "do {} while(0);". This version makes less assumptions about what the original code looked like. --- src/code/PreRender.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) (limited to 'src/code') diff --git a/src/code/PreRender.c b/src/code/PreRender.c index 94afbafb7..bc65fe3a0 100644 --- a/src/code/PreRender.c +++ b/src/code/PreRender.c @@ -308,14 +308,13 @@ void func_800C2118(PreRenderContext* this, Gfx** gfxp) { func_800C0F28(this, gfxp, this->zbufSave, this->zbuf); } -#ifdef NON_MATCHING -// regalloc differences in gDPLoadMultiTile void func_800C213C(PreRenderContext* this, Gfx** gfxp) { Gfx* gfx; s32 y; s32 y2; s32 add; s32 uls; + s32 yinc; // vertical increment amount s32 ult; s32 lrx; s32 lry; @@ -350,20 +349,23 @@ void func_800C213C(PreRenderContext* this, Gfx** gfxp) { } uls = 0; + yinc = 1; ult = y2; - lry = (y2 + add - 1); + lry = (y2 + add - yinc); gDPLoadMultiTile(gfx++, this->fbufSave, 0x0000, G_TX_RENDERTILE, G_IM_FMT_RGBA, G_IM_SIZ_16b, this->width, this->height, uls, ult, lrx, lry, 0, G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMASK, G_TX_NOMASK, G_TX_NOLOD, G_TX_NOLOD); - gDPLoadMultiTile(gfx++, this->cvgSave, 0x0160, 1, G_IM_FMT_I, G_IM_SIZ_8b, this->width, this->height, uls, ult, + + do {} while(0); // force register allocation behavior + gDPLoadMultiTile(gfx++, this->cvgSave, 0x0160, yinc, G_IM_FMT_I, G_IM_SIZ_8b, this->width, this->height, uls, ult, lrx, lry, 0, G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMASK, G_TX_NOMASK, G_TX_NOLOD, G_TX_NOLOD); - gSPTextureRectangle(gfx++, uls << 2, ult << 2, (lrx + 1) << 2, (lry + 1) << 2, G_TX_RENDERTILE, uls << 5, + do {} while(0); // force register allocation behavior + gSPTextureRectangle(gfx++, uls << 2, ult << 2, (lrx + yinc) << 2, (lry + yinc) << 2, G_TX_RENDERTILE, uls << 5, ult << 5, 1 << 10, 1 << 10); - if (1) {} y -= add; y2 += add; } @@ -371,9 +373,6 @@ void func_800C213C(PreRenderContext* this, Gfx** gfxp) { gDPPipeSync(gfx++); *gfxp = gfx; } -#else -#pragma GLOBAL_ASM("asm/non_matchings/code/PreRender/func_800C213C.s") -#endif void func_800C24BC(PreRenderContext* this, Gfx** gfxp) { func_800C0F28(this, gfxp, this->fbufSave, this->fbuf); -- cgit v1.2.3